JP7149107B2 - fuel injector - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve applied to fuel injection of a marine diesel engine mounted on a ship.

Conventionally, in the field of ships, fuel and water are injected from the same fuel injection valve into the combustion chamber in the cylinder as a method of reducing nitrogen oxides (NOx) generated during internal combustion of marine diesel engines. It is valid to For example, in Patent Document 1, high-pressure water that has passed through a water injection check valve from a water passage in a valve body is injected into fuel pressure-fed from a fuel injection pump into a fuel oil passage, and is injected into a combustion chamber in a cylinder. On the other hand, a fuel injection valve has been proposed that injects fuel and water in three stages in the order of fuel-water-fuel in one injection cycle.

In such a fuel injection valve, communication between a fuel oil passage and an injection hole (injection port) is generally blocked by a needle valve so as to be openable. Specifically, the needle valve is slidably provided inside the fuel injection valve, and the sac portion (liquid pool portion) communicating between the fuel oil passage and the injection hole is controlled by the biasing force of the needle valve spring. releasably occluded. The fuel pressure-fed from the fuel injection pump remains in the sack portion, and the sack portion is closed by the needle valve when the pressure of this fuel is equal to or lower than the biasing force of the needle valve spring applied to the needle valve. be. In this case, communication between the fuel oil passage and the injection hole is cut off. On the other hand, when the fuel pressure-fed from the fuel injection pump is newly introduced into the sack portion through the fuel oil passage, the pressure of the fuel in the sack portion increases and exceeds the biasing force of the needle valve spring. slides against the urging force of the needle valve spring, thereby opening the sac portion. In this case, the communication between the fuel oil passage and the nozzle hole is open, and as described above, the fuel pressure-fed from the fuel injection pump into the fuel oil passage and the water injection check valve from the water passage in the valve body are connected. The water injected into the fuel oil passage through the nozzle hole is injected into the combustion chamber.

JP-A-6-66217

However, in the above-described prior art, high-pressure fuel (for example, pressure of 800 to 1000 bar) pressurized by the fuel injection pump is introduced into the sack from one side through the fuel oil passage. The pressure of the fuel is unevenly applied, and due to this, the needle valve may slide in a tilted state. In this case, not only the sliding needle valve itself, but also the surface rubbed by the sliding of the needle valve (for example, the inner wall surface of a housing part that houses the needle valve in the fuel injection valve, etc.), and the needle valve Sliding parts (for example, parts that transmit the urging force of the needle valve spring to the needle valve, etc.) may wear out and become easily damaged.

In addition, in the above-described prior art, since water is injected from one side into the fuel oil passage through the water injection check valve from the water passage in the valve body, the water is uniformly injected into the fuel in the fuel oil passage. is often difficult. In the water injection technology, which alternately injects fuel and water into the combustion chamber in the cylinder, from the viewpoint of improving the fuel efficiency and NOx reduction performance of marine diesel engines, water is uniformly distributed in the fuel in the fuel oil passage. to form a uniform water injection layer (layer of water injected into the fuel oil passage) in the fuel layer (layer of fuel formed in the fuel oil passage) in one cycle injection preferable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. It is an object of the present invention to provide a fuel injector that can be injected.

In order to solve the above-described problems and achieve the object, a fuel injection valve according to the present invention is a fuel injection valve that injects fuel and water from nozzle holes into a combustion chamber in a cylinder of a marine diesel engine. a fuel oil passage for circulating the fuel pressure-fed from, a needle valve for blocking communication between the fuel oil passage and the injection hole so as to be openable, and a needle valve for blocking communication between the fuel oil passage and the injection hole a needle valve spring for urging the needle valve toward the nozzle hole side; a water injection passage for injecting the water into a predetermined position of the fuel oil passage; and between the needle valve and the needle valve spring. a water injection check valve that is interposed and blocks communication between the fuel oil passage and the water injection passage so as to be openable, and the water injection passage is formed axially symmetrically about the central axis of the operation direction of the water injection check valve. and a symmetrical water injection passage having a discharge port facing the water injection check valve.

Further, in the fuel injection valve according to the present invention, in the above invention, the water injection check valve includes a valve body provided with a pressure receiving portion that receives pressure of the water from the symmetrical water injection passage over the outer periphery. characterized by

Further, in the fuel injection valve according to the present invention, in the above invention, the symmetrical water injection passage is composed of a plurality of water passages formed at equal angular intervals around the central axis of the operation direction of the water injection check valve. and

Further, in the fuel injection valve according to the present invention, in the above invention, the water injection passage has an annular water injection passage that surrounds the water injection check valve.

ADVANTAGE OF THE INVENTION According to this invention, while suppressing the situation where sliding components, such as a needle valve, incline with respect to a sliding direction, it is effective in injecting water uniformly in the fuel in a fuel oil path.

FIG. 1 is a schematic cross-sectional view showing one configuration example of a fuel injection valve according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the fuel injection valve shown in FIG. 1 taken along the line AA. FIG. 3 is a schematic cross-sectional view of the fuel injection valve shown in FIG. 1 taken along line BB.

A preferred embodiment of a fuel injection valve according to the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited by this embodiment. Also, it should be noted that the drawings are schematic, and the dimensional relationship of each element, the ratio of each element, and the like may differ from the actual ones. Even between the drawings, there are cases where portions with different dimensional relationships and ratios are included. Moreover, in each drawing, the same code|symbol is attached|subjected to the same component.

(Structure of fuel injection valve)
First, the configuration of the fuel injection valve according to the embodiment of the present invention will be described. FIG. 1 is a schematic cross-sectional view showing one configuration example of a fuel injection valve according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the fuel injection valve shown in FIG. 1 taken along the line AA. FIG. 3 is a schematic cross-sectional view of the fuel injection valve shown in FIG. 1 taken along line BB. In FIG. 1 , the axial direction F1 is the direction of the longitudinal center axis of the fuel injection valve 100 . In this embodiment, in order to facilitate the explanation of the configuration of the fuel injection valve 100, the positive side in the axial direction F1 is the front end side of the fuel injection valve 100, and the negative side in the axial direction F1 is the rear end side of the fuel injection valve 100. and The radial direction F2 is the radial direction of the fuel injection valve 100 and is a direction perpendicular to the longitudinal central axis of the fuel injection valve 100 .

The fuel injection valve 100 according to the present embodiment is attached to a cylinder (not shown) of a marine diesel engine, and is pressure-fed from a fuel injection pump (not shown) and a water injection pump (not shown). It is for sequentially injecting water and water into the combustion chamber in the cylinder (for example, stratified injection). As shown in FIG. 1, the fuel injection valve 100 includes a nozzle 1 positioned at the tip, an injection valve main body 11 positioned on the rear end side of the nozzle 1, and an injection valve positioned on the rear end side of the injection valve main body 11. a main body 40; The nozzle 1 and the injection valve main body 11 are fixed in a state of being connected in the axial direction F1 by being fastened from the outer circumference by a nut-shaped nozzle clamping metal 10. As shown in FIG. The injection valve main body 11 and the injection valve main body 40 on the rear end side are fixed in a state of being connected in the axial direction F1 by fastening from the outer periphery with a nut-like valve main body tightening metal fitting 30 .

The nozzle 1 constitutes the tip portion of the fuel injection valve 100 . As shown in FIG. 1, the nozzle 1 is provided with a hole-shaped needle valve accommodating portion 2 elongated in the axial direction F1. A needle valve 6 is slidably accommodated in the needle valve accommodating portion 2 for releasably blocking the communication between the fuel oil passage of the fuel injection valve 100 and the injection hole 4 . Inside the needle valve 6, a needle valve internal oil passage 7 is provided which extends in the axial direction F1. A storage portion 3 is formed between the tip side of the needle valve accommodating portion 2 and the tip side of the needle valve 6 . A communicating hole 8 is provided at the distal end of the needle valve 6 to allow the oil passage 7 in the needle valve and the reservoir 3 to communicate with each other. An injection hole 4 and a tip oil passage 5 are provided on the tip side of the nozzle 1 . One end of the tip oil passage 5 communicates with the fuel oil passage of the fuel injection valve 100 (specifically, the needle valve inner oil passage 7 which is part of the fuel oil passage of the fuel injection valve 100). The other end of the tip oil passage 5 communicates with the nozzle hole 4 .

The injection valve main body 11 constitutes an intermediate portion between the nozzle 1 on the front end side and the injection valve main body 40 on the rear end side. As shown in FIG. 1, the injection valve body 11 is provided with a hole-shaped check valve accommodating portion 12 that extends in the axial direction F1. A water injection check valve 20 corresponding to the first water injection passage of the fuel injection valve 100 is housed in the check valve housing portion 12 . In the present embodiment, the first water injection passage is a water passage for injecting water into a predetermined position (first water injection position P1 shown in FIG. 1) in the fuel oil passage of fuel injection valve 100 .

The water injection check valve 20 is a check valve (first water injection check valve) that opens and closes the first water injection passage of the fuel injection valve 100 . As shown in FIG. 1, the water injection check valve 20 is composed of a valve body 21, a valve seat 24, a check valve spring 26, and a valve body receiving portion 27. It is arranged on the hole 4 side.

As shown in FIG. 1, the valve body 21 has a pressure receiving portion 23 that receives the pressure of water from the first water injection passage, and is slidably accommodated in a valve body receiving portion 27 . As shown in FIGS. 1 and 2, the pressure receiving portion 23 is formed in an annular shape over the outer periphery of the valve body 21 near the tip. A valve internal oil passage 22 that is a part of the fuel oil passage of the fuel injection valve 100 is provided in the valve body 21 . As shown in FIG. 1, the valve seat 24 is fixed to the tip of the valve body receiving portion 27 by fastening or the like. In the valve seat 24 , an in-seat oil passage 25 that is a part of the fuel oil passage of the fuel injection valve 100 is provided. The check valve spring 26 is arranged between the rear end portion of the valve body 21 and the valve body receiving portion 27, as shown in FIG. The check valve spring 26 applies an urging force to the valve body 21 to urge the valve seat 24 side. The water injection check valve 20 utilizes the urging force of the check valve spring 26 to press the valve body 21 against the valve seat 24, thereby creating a connection between the fuel oil passage of the fuel injection valve 100 and the first water injection passage. Cut off the communication so that it can be opened.

Further, in this embodiment, the water injection check valve 20 has both the function of the check valve and the function of a push rod that transmits the biasing force of the needle valve spring 50 to the needle valve 6 . Specifically, as shown in FIG. 1 , the water injection check valve 20 is interposed between the needle valve 6 and the needle valve spring 50 . For example, the water injection check valve 20 is in a state in which the needle valve spring 50 is received by the rear end portion of the valve body receiving portion 27 and the front end portion of the valve seat 24 is pressed against the rear end portion of the needle valve 6 . . The water injection check valve 20 is slidable in the axial direction F<b>1 within the check valve accommodating portion 12 , and uses the biasing force of the needle valve spring 50 to press the needle valve 6 against the tip oil passage 5 . In addition, the water injection check valve 20 slides along with the needle valve 6 in the direction away from the tip oil passage 5 using the pressure of the fuel in the reservoir 3, and in the direction ( direction to compress the needle valve spring 50).

Further, as shown in FIG. 1, the injection valve main body 11 is provided with a columnar water injection passage 72, annular water injection passages 73 and 75, and a symmetrical water injection passage 74. A water inlet 76 is provided. The columnar water injection passage 72 is a columnar water passage, and is bored in the rear end portion of the injection valve main body 11 . The annular water injection passage 73 is formed by a gap between the inner wall surface of the valve body clamping hardware 30 and the outer wall surface of the injection valve body 11. For example, as shown in FIGS. 27, etc.). The symmetrical water injection channel 74 is a water channel formed axially symmetrically about the central axis of the water injection check valve 20 in the operating direction. In this embodiment, as shown in FIGS. 1 and 2, the symmetrical water injection passages 74 are formed (drilled) in the injection valve main body 11 at equal angular intervals around the central axis of the operation direction of the water injection check valve 20. It consists of a plurality of (for example, four) channels. The annular water injection passage 75 is configured by, for example, a groove or the like provided in the inner peripheral surface of the injection valve main body 11 (the inner wall surface of the check valve accommodating portion 12). 1 and 2, the annular water injection channel 75 is positioned between the outlet end of the symmetrical water injection channel 74 and the inlet end of the symmetrical water injection channel 76, and accommodates the water injection check valve 20 (valve receiver 27, etc.). It is formed in an enclosing ring. The symmetrical water injection channel 76 is formed axially symmetrically about the central axis of the operation direction of the water injection check valve 20 and has a discharge port facing the water injection check valve 20 (specifically, the pressure receiving portion 23 of the valve body 21). be. In this embodiment, as shown in FIGS. 1 and 2, the symmetrical water injection passages 76 are formed (pierced) in the valve body receiving portion 27 at equal angular intervals around the central axis of the operation direction of the water injection check valve 20. It consists of multiple (for example, four) waterways.

The central axis in the operation direction of the water injection check valve 20 is the central axis in the sliding direction of the valve body 21 . In this embodiment, the central axis in the operating direction of the water injection check valve 20 is aligned with or parallel to the longitudinal central axis of the fuel injection valve 100 .

The columnar water injection passage 72 , the annular water injection passages 73 and 75 and the symmetrical water injection passages 74 and 76 described above are water passages that form part of the first water injection passage of the fuel injection valve 100 . As shown in FIGS. 1 and 2, the columnar water injection channel 72 leads to the annular water injection channel 73, the annular water injection channel 73 leads to the symmetrical water injection channel 74, the symmetrical water injection channel 74 leads to the annular water injection channel 75, and the annular water injection channel 75 It leads to a symmetrical water injection channel 76 . Also, the symmetrical water injection passage 76 communicates with the first water injection position P1 in the fuel oil passage of the fuel injection valve 100 when the valve body 21 is separated from the valve seat 24 . In addition, as shown in FIG. 1, on the outer wall surface of the injection valve main body 11, a water leakage prevention valve from the annular water injection passage 73 and the like is provided at a position between the annular water injection passage 73 and the tip of the valve body clamping fitting 30. An O-ring 91 is provided for this purpose.

On the other hand, the injection valve main body 40 constitutes the rear end portion of the fuel injection valve 100 . As shown in FIG. 1, the injection valve main body 40 is provided with a hole-shaped accommodating portion 41 elongated in the axial direction F1. The housing portion 41 houses a needle valve spring 50 , a spring receiving portion 51 , and a water injection check valve 60 corresponding to the second water injection passage of the fuel injection valve 100 . In the present embodiment, the second water injection passage is located upstream of the first water injection passage in the fuel pressure feeding direction (for example, the second water injection position P2 shown in FIG. 1) in the fuel oil passage of the fuel injection valve 100. It is a channel for injecting water into the

The needle valve spring 50 biases the needle valve 6 toward the nozzle hole 4 so as to close the tip oil passage 5 . As shown in FIG. 1 , the needle valve spring 50 is composed of, for example, a coil spring, and is housed in the housing section 41 while attached to the spring receiving section 51 . The spring receiving portion 51 is accommodated in the accommodating portion 41 while receiving the needle valve spring 50, and is inserted into the insertion hole 29 formed at the rear end portion of the valve body receiving portion 27 of the water injection check valve 20 described above. Attached slidably. The spring receiving portion 51 receives one end portion of the needle valve spring 50 and presses the other end portion of the needle valve spring 50 against the rear end portion of the valve body receiving portion 27, thereby compressing the needle valve spring 50 with a biasing force. generate In addition, a spring receiving portion internal oil passage 52 that is a part of the fuel oil passage of the fuel injection valve 100 is provided in the spring receiving portion 51 .

The water injection check valve 60 is a check valve (second water injection check valve) that opens and closes the second water injection passage of the fuel injection valve 100 . As shown in FIG. 1, the water injection check valve 60 includes a valve body 61, a valve seat 64, a check valve spring 66, and a valve body receiving portion 67. 4 is placed on the opposite side. In this embodiment, the water injection check valve 60 corresponding to the second water injection passage and the water injection check valve 20 corresponding to the first water injection passage are arranged on opposite sides in the axial direction F1 with the needle valve spring 50 therebetween. placed. At this time, these two water injection check valves 20 and 60 are preferably arranged on the same axis in the axial direction F1.

As shown in FIG. 1, the valve body 61 has a pressure receiving portion 63 that receives the pressure of water from the second water injection channel, and is slidably accommodated in a valve body receiving portion 67 . As shown in FIGS. 1 and 3, the pressure receiving portion 63 is formed in an annular shape around the outer periphery of the valve body 61 near the tip. A valve internal oil passage 62 that is a part of the fuel oil passage of the fuel injection valve 100 is provided in the valve body 61 . The valve seat 64 is fixed to the tip of the valve body receiving portion 67 by fastening or the like, as shown in FIG. In the valve seat 64 , an in-seat oil passage 65 that is a part of the fuel oil passage of the fuel injection valve 100 is provided. The check valve spring 66 is arranged between the rear end portion of the valve body 61 and the valve body receiving portion 67, as shown in FIG. The check valve spring 66 applies an urging force to the valve body 61 to urge the valve seat 64 side. The water injection check valve 60 utilizes the biasing force of the check valve spring 66 to press the valve body 61 against the valve seat 64, thereby creating a connection between the fuel oil passage of the fuel injection valve 100 and the second water injection passage. Cut off the communication so that it can be opened. The valve body receiving portion 67 is configured to be screwed into the housing portion 41 of the injection valve main body 40 . Inside the valve body receiving portion 67, a receiving portion internal oil passage 68, which is a part of the fuel oil passage of the fuel injection valve 100, is provided. Further, as shown in FIG. 1, a fuel supply pipe 90 is connected to the rear end portion of the valve body receiving portion 67 and communicates with the receiving portion internal oil passage 68 . The fuel supply pipe 90 is a pipe for introducing fuel pressure-fed by a fuel injection pump (not shown) into the fuel oil passage of the fuel injection valve 100 .

In the present embodiment, the water injection check valve 60 functions as the above-described check valve and as an adjusting screw for adjusting the biasing force of the needle valve spring 50 (that is, the valve opening pressure of the needle valve 6). Combines. Specifically, as shown in FIG. 1 , the water injection check valve 60 is attached by screwing the valve body receiving portion 67 into the housing portion 41 of the injection valve main body 40 . The water injection check valve 60 screwed into the housing portion 41 is in a state where the front end portion of the valve seat 64 is in contact with the rear end portion of the spring receiving portion 51 . The water injection check valve 60 adjusts the biasing force of the needle valve spring 50 by adjusting the amount of screwing into the housing portion 41 . Specifically, the amount of compression of the needle valve spring 50 is increased by increasing the amount of screwing into the accommodating portion 41 and increasing the amount of pushing the spring receiving portion 51 toward the nozzle hole 4 . Increase to adjust the urging force strongly. On the other hand, the water injection check valve 60 is attached by reducing the amount of compression of the needle valve spring 50 by reducing the amount of screwing into the housing portion 41 and reducing the amount of pushing the spring receiving portion 51 into the injection hole 4 side. Adjust the strength to be weak.

As shown in FIGS. 1 and 3, columnar water injection passages 71 and 81 are provided in the injection valve body 40, and an annular water injection passage 82 and a symmetrical water injection passage 84 are provided in the valve body receiving portion 67 of the water injection check valve 60. is provided. The columnar water injection passages 71 and 81 are columnar water passages and are drilled at different positions in the injection valve body 40 . The annular water injection channel 82 is configured by, for example, a groove or the like provided on the outer peripheral surface of the valve body receiving portion 67 . As shown in FIG. 3, the annular water injection channel 82 is located between the outlet end of the columnar water injection channel 81 and the inlet end of the symmetrical water injection channel 84, and surrounds the water injection check valve 60 (valve body 61, etc.). It is formed. The symmetrical water injection channel 84 is formed axially symmetrical about the central axis of the operation direction of the water injection check valve 60 and has a discharge port facing the water injection check valve 60 (specifically, the pressure receiving portion 63 of the valve body 61). be. In this embodiment, as shown in FIGS. 1 and 3, the symmetrical water injection passages 84 are formed (drilled) in the valve body receiving portion 67 at equal angular intervals around the central axis of the operation direction of the water injection check valve 60. It consists of multiple (for example, four) waterways.

The central axis of the water injection check valve 60 in the operating direction is the central axis of the valve body 61 in the sliding direction. In this embodiment, the central axis in the operating direction of the water injection check valve 60 is aligned with or parallel to the longitudinal central axis of the fuel injection valve 100 .

The columnar water injection channel 71 described above is a water channel that forms part of the first water injection channel of the fuel injection valve 100 . As shown in FIG. 1, the columnar water injection channel 71 communicates with the columnar water injection channel 72 in the injection valve main body 11 described above. On the other hand, the columnar water injection channel 81 , the annular water injection channel 82 and the symmetrical water injection channel 84 described above are water channels that form part of the second water injection channel of the fuel injection valve 100 . As shown in FIGS. 1 and 3 , columnar water injection channel 81 leads to annular water injection channel 82 , and annular water injection channel 82 leads to symmetrical water injection channel 84 . Also, the symmetrical water injection passage 84 communicates with the second water injection position P2 in the fuel oil passage of the fuel injection valve 100 when the valve body 61 is separated from the valve seat 64 . Further, as shown in FIG. 1, O-rings 92 and 93 for preventing water leakage from the annular water injection passage 82 and the like are provided on the outer peripheral surface of the valve body receiving portion 67 at respective positions sandwiching the annular water injection passage 82. It is

(fuel oil passage)
Next, the fuel oil passage of the fuel injection valve 100 according to this embodiment will be described. The fuel oil passage of the fuel injection valve 100 is a passage (oil passage) through which the fuel pressure-fed from the fuel injection pump flows. In this embodiment, the fuel oil passages of the fuel injection valve 100 include the needle valve inner oil passage 7, the valve inner oil passages 22 and 62, the valve seat inner oil passages 25 and 65, and the receiver inner oil passages. 28 , 68 and the oil passage 52 in the spring receiving portion.

Specifically, as shown in FIG. 1, in the fuel oil passage of the fuel injection valve 100, the needle valve inner oil passage 7 communicates with the valve seat oil passage 25, and the valve seat oil passage 25 communicates with the valve body. It communicates with the oil passage 22 , and the in-valve oil passage 22 communicates with the in-receptacle oil passage 28 . Further, the receiving portion inner oil passage 28 communicates with the spring receiving portion inner oil passage 52 , and the spring receiving portion inner oil passage 52 communicates with the valve seat inner oil passage 65 . Further, the in-seat oil passage 65 communicates with the in-valve oil passage 62 , and the in-valve oil passage 62 communicates with the in-receiving portion oil passage 68 . The fuel oil passages of the fuel injection valve 100 configured by these oil passages are arranged, for example, as shown in FIG. It is Further, the tip side (injection hole 4 side) of the fuel oil passage of the fuel injection valve 100 communicates with the reservoir 3 from the needle valve internal oil passage 7 via the communication hole 8 of the needle valve 6 . The rear end side (fuel injection pump side) of the fuel oil passage of the fuel injection valve 100 communicates with the fuel supply pipe 90 via the receiving portion inner oil passage 68 .

(First water injection channel and second water injection channel)
Next, the first water injection passage and the second water injection passage of the fuel injection valve 100 according to this embodiment will be described. In this embodiment, the first water injection passage is a passage ( waterway). As shown in FIGS. 1 and 2, the first water injection channel communicates with the columnar water injection channel 71, the columnar water injection channel 72, the annular water injection channel 73, the symmetrical water injection channel 74, the annular water injection channel 75, and the symmetrical water injection channel 76 in this order. It is constructed by letting Also, the first water injection channel communicates with the water injection pump from the columnar water injection channel 71 via a water supply pipe (not shown). Also, the annular water injection channel 73 is formed in a ring shape surrounding the water injection check valve 20 , so that the water distribution range is wider than the columnar water injection channels 71 and 72 . Therefore, even if the annular water injection channel 73 has a channel width smaller than that of the columnar water injection channels 71 and 72 in the radial direction F2, the channel volume per unit length in the axial direction F1 is the same as that of the columnar water injection channels 71 and 72. maintained to

Further, in the present embodiment, the second water injection passage is for injecting water pressure-fed from the water injection pump into the second water injection position P2 of the fuel oil passage of the fuel injection valve 100 via the water injection check valve 60. It is a passage (waterway). The second water injection channel, as shown in FIGS. 1 and 3, is configured by connecting a columnar water injection channel 81, an annular water injection channel 82, and a symmetrical water injection channel 84 in this order. The second water injection channel communicates with the water injection pump from the columnar water injection channel 81 via a water supply pipe (not shown). The water injection pump that pressure-feeds water to the second water injection path may be the same as the water injection pump that pressure-feeds water to the first water injection path described above, or may be different.

(Action of fuel injection valve)
Next, the action of the fuel injection valve 100 according to this embodiment will be described. The fuel injection valve 100 injects fuel and water in layers from the injection hole 4 into a combustion chamber in a cylinder of a marine diesel engine in one injection cycle.

During the period from the end of this one cycle injection to the next injection (hereinafter referred to as a non-fuel injection period), the fuel flow from the fuel oil passage of the fuel injection valve 100 to the tip oil passage 5 via the reservoir 3 Fuel pumped from the fuel injection pump remains in the flow path and fuel supply pipe 90 . At this stage, the pressure of the fuel remaining in reservoir 3 is lower than the opening pressure of needle valve 6 . Therefore, the needle valve 6 is in a state in which the tip oil passage 5 can be opened and closed. The valve opening pressure of the needle valve 6 is the pressure required to open the needle valve 6 and is set by the biasing force of the needle valve spring 50 transmitted to the needle valve 6 via the water injection check valve 20 .

During this non-fuel injection period, water pumped from the water injection pump remains inside the first water injection passage and the second water injection passage of the fuel injection valve 100 . At this stage, the pressure of the water remaining in the first water injection channel is lower than the opening pressure of the water injection check valve 20 . Therefore, the water injection check valve 20 is in a state of being able to open the communication between the fuel oil passage of the fuel injection valve 100 and the first water injection passage. Similarly, since the pressure of the water remaining in the second water injection passage is lower than the valve opening pressure of the water injection check valve 60, the water injection check valve 60 is connected to the fuel oil passage of the fuel injection valve 100. Communication with the second water injection channel is cut off so as to be openable. The opening pressure of the water injection check valve 20 is the pressure required to open the water injection check valve 20, and is set by the biasing force of the check valve spring 26 that presses the valve body 21 against the valve seat 24. . The opening pressure of the water injection check valve 60 is the pressure required to open the water injection check valve 60 and is set by the biasing force of the check valve spring 66 that presses the valve element 61 against the valve seat 64 .

Here, in this non-fuel injection period, when high-pressure water exceeding the valve opening pressure of the water injection check valve 20 is pressure-fed from the water injection pump into the first water injection passage of the fuel injection valve 100, this high-pressure water is , columnar water injection channels 71 and 72, annular water injection channel 73, symmetrical water injection channel 74, annular water injection channel 75 and symmetrical water injection channel 76 shown in FIGS. This high-pressure water flows through the discharge port of the symmetrical water-injection passage 76 so as to press the valve body 21 from the axially symmetrical direction with respect to the central axis of the water-injection check valve 20 in the operating direction. That is, the valve body 21 receives the pressure of this high-pressure water (water pressure) at the pressure receiving portion 23 in an axially symmetrical manner. Since this water pressure is higher than the valve opening pressure of the water injection check valve 20, the valve element 21 slides against the biasing force of the check valve spring 26 using this water pressure, and the valve seat 24 is closed. move away from Thus, the water injection check valve 20 opens communication between the fuel oil passage of the fuel injection valve 100 and the first water injection passage.

At this stage, the water in the first water injection passage is injected into the fuel oil passage of the fuel injection valve 100 from the arrangement position of the water injection check valve 20 . Specifically, the water in the first water injection passage flows from the direction of axis symmetry with respect to the fuel flow direction central axis of the fuel oil passage of the fuel injection valve 100 (for example, the longitudinal central axis of the fuel injection valve 100). It is injected into the first water injection position P1 in the channel. The injected water spreads axially symmetrically (uniformly in the radial direction F2) within the fuel oil passage, pushing back the residual fuel in the fuel oil passage toward the rear end side (fuel injection pump side) in the axial direction F1. . As a result, a first water-filled layer is formed in the fuel oil passage as the first water-filled layer. A first fuel layer made of fuel remaining in the fuel oil passage on the side of the injection hole 4 relative to the first water injection position P1 is formed downstream of the first injection layer (on the side of the injection hole 4).

On the other hand, in this non-fuel injection period, when high-pressure water exceeding the valve opening pressure of the water injection check valve 60 is force-fed from the water injection pump into the second water injection passage of the fuel injection valve 100, this high-pressure water The water flows through the insides of the columnar water injection channel 81, the annular water injection channel 82 and the symmetrical water injection channel 84 shown in FIGS. 1 and 3 in this order. This high-pressure water flows through the discharge port of the symmetrical water-injection passage 84 so as to press the valve body 61 from the axially symmetrical direction with respect to the central axis of the water-injection check valve 60 in the operating direction. That is, the valve body 61 receives the water pressure of this high-pressure water at the pressure receiving portion 63 in an axially symmetrical manner. Since this water pressure is higher than the valve opening pressure of the water injection check valve 60, the valve element 61 slides against the biasing force of the check valve spring 66 using this water pressure, and the valve seat 64 move away from Thus, the water injection check valve 60 opens communication between the fuel oil passage of the fuel injection valve 100 and the second water injection passage.

At this stage, the water in the second water injection passage is injected into the fuel oil passage of the fuel injection valve 100 from the arrangement position of the water injection check valve 60 . Specifically, the water in the second water injection passage is injected into the second water injection position P2 in the fuel oil passage from the axially symmetrical direction with respect to the central axis of the fuel oil passage of the fuel injection valve 100 in the fuel flow direction. . The injected water spreads axially symmetrically (uniformly in the radial direction F2) within the fuel oil passage, pushing back the residual fuel in the fuel oil passage toward the rear end side (fuel injection pump side) in the axial direction F1. . As a result, a second water-filled layer, which is the second water-filled layer, is formed in the fuel oil passage. A second fuel layer composed of fuel remaining in the fuel oil passage is formed between the second water-filled layer and the first water-filled layer. A third fuel layer is formed on the upstream side (on the side of the fuel injection pump) of the second water injection layer, which consists of fuel remaining in the fuel oil passage on the fuel injection pump side of the second water injection position P2.

After the non-fuel injection period described above, the fuel is pumped from the fuel injection pump into the fuel oil passage of the fuel injection valve 100, and the fuel and water are injected into the combustion chamber in the cylinder of the marine diesel engine in one cycle. is done.

More specifically, during the period during which this injection is performed (hereinafter referred to as the fuel injection period), fuel at a pressure higher than the valve opening pressure of the needle valve 6 flows from the fuel injection pump through the fuel supply pipe 90 to the fuel injection valve 100. pumped into the road. In this case, the pressure of the fuel pressure-fed from the fuel injection pump flows from the communication hole 8 of the needle valve 6 through the fluid (remaining fuel and injected water) existing in the fuel flow path of the fuel injection valve 100. It is transmitted to the fuel in the reservoir 3 . As a result, the pressure of the fuel in the reservoir 3 is raised higher than the opening pressure of the needle valve 6 . The needle valve 6 receives the pressure of the increased fuel in the reservoir 3 at its tip portion, and utilizes this fuel pressure to slide against the biasing force of the needle valve spring 50, thereby opening the tip oil passage. It is separated from the opening (seat portion) of 5. At this time, the water injection check valve 20 slides together with the needle valve 6 in a direction (rear end side in the axial direction F1) against the biasing force of the needle valve spring 50 . In this manner, the needle valve 6 opens communication between the fuel oil passage of the fuel injection valve 100 and the nozzle hole 4 .

At this stage, the fuel injector 100 injects one cycle of fuel and water into the combustion chamber within the cylinder of the marine diesel engine. For example, the fuel injection valve 100 causes the first fuel layer, the first water-filled layer, the second fuel layer, the second water-filled layer and the third fuel layer in the fuel oil passage to be injected in this order from the injection hole 4 into the cylinder. Spray into the chamber in layers. After that, the pressure of the fuel in the reservoir 3 is reduced below the opening pressure of the needle valve 6 . In this case, the needle valve 6 utilizes the biasing force of the needle valve spring 50 to slide toward the nozzle hole 4 and contact the seat portion of the tip oil passage 5 again to open and close the tip oil passage 5 . do. In this manner, the needle valve 6 cuts off communication between the fuel oil passage of the fuel injection valve 100 and the nozzle hole 4 so as to be openable.

As described above, in the fuel injection valve 100 according to the embodiment of the present invention, the needle valve 6 for releasably blocking the communication between the fuel oil passage through which the fuel pressure-fed from the fuel injection pump flows and the injection hole 4 , a needle valve spring 50 that biases the needle valve 6 toward the nozzle hole 4, and a first water injection passage for injecting water into the first water injection position P1 of the fuel oil passage and the fuel oil passage are in communication. , and the water injection check valve 20 is arranged to be interposed between the needle valve 6 and the needle valve spring 50 . In addition, the first water injection passage is configured to have a symmetrical water injection passage 76 having a discharge port formed axially symmetrically with respect to the central axis of the operation direction of the water injection check valve 20, and the symmetrical water injection passage 76 is the discharge port. The outlet and the water injection check valve 20 are arranged to face each other.

Therefore, the water injection check valve 20 is pressed against the needle valve 6 by the urging force of the needle valve spring 50, and the water injection check valve 20 and the needle valve 6 can be integrally connected. As a result, inclination (deformation) of the needle valve 6 in the sliding direction can be suppressed by the pressing action of the water injection check valve 20 that presses the needle valve 6 using the biasing force of the needle valve spring 50 . Furthermore, when opening the water injection check valve 20, the water pressure from the first water injection passage can be applied to the water injection check valve 20 axially symmetrically. Inclination of the water injection check valve 20 with respect to the central axis of the operation direction can be suppressed. By suppressing the inclination of the water-filling check valve 20, the needle valve 6 integrally connected with the water-filling check valve 20 can be prevented from tilting in the sliding direction. As a result, the needle valve 6 and the water injection check valve 20 that slides integrally with the needle valve 6 can be prevented from tilting in the sliding direction. Damage can be suppressed.

Further, as described above, the inclination of the sliding parts is suppressed, and water is axially symmetrically injected into the first water injection position P1 in the fuel oil passage through the water injection check valve 20 from the discharge port of the first water injection passage. be able to. As a result, water can be uniformly injected into the fuel in the fuel oil passage, and a uniform water-filled layer can be formed in the fuel. As a result, by injecting fuel and water in one cycle, a uniform fuel layer and a water injection layer can be sequentially injected into the combustion chamber in the cylinder, which can contribute to the improvement of fuel efficiency and NOx reduction performance of marine diesel engines. can.

Further, in the fuel injection valve 100 according to the embodiment of the present invention, the valve body of the water injection check valve is provided with a pressure receiving portion that receives pressure of water from the symmetrical water injection passages over the outer circumference. Therefore, the valve element of the water injection check valve can efficiently receive the pressure of water from the symmetrical water injection passage by the pressure receiving portion in an axially symmetrical manner. As a result, it is possible to efficiently slide the valve body while suppressing the inclination of the valve body in the sliding direction.

Further, in the fuel injection valve 100 according to the embodiment of the present invention, the first water injection passage is configured to have an annular water injection passage 73 that surrounds the water injection check valve 20 . Here, since the annular water injection channel 73 can annularly expand the water distribution range, even if the water channel width in the radial direction F2 is smaller than that of the columnar water channel, the water channel per unit length in the axial direction F1 The volume can be made equivalent to a columnar channel. Therefore, it is possible to reduce the channel width in the region of the annular water injection channel 73 of the first water injection channel without hindering the flow of water in the first water injection channel. It is possible to promote miniaturization in the radial direction F2.

In the above-described embodiment, as an example of symmetrical water injection passages for discharging water to the valve body of the water injection check valve, four water passages formed at equal angular intervals around the central axis of the operation direction of the water injection check valve Although a symmetrical water injection channel is illustrated as an example, the present invention is not limited to this. In the present invention, the symmetrical water injection channel may consist of two or more (a plurality of) water channels formed at equal angular intervals around the central axis of the operation direction of the water injection check valve. It may consist of a single annular waterway with a continuous annular outlet around the central axis in the direction of movement of the .

Moreover, in the above-described embodiment, an example of the first water injection channel and the second water injection channel has been illustrated as having a ring-shaped water injection channel, but the present invention is not limited to this. For example, the first water injection channel and the second water injection channel directly communicate the symmetrical water injection channel with the discharge port facing the valve body of the water injection check valve and the columnar water injection channel that receives water pressure-fed from the water injection pump. It may be one that has been made

Further, in the above-described embodiment, as an example of the valve body of the water injection check valve, the valve body provided with the pressure receiving portion on the outer periphery that receives the pressure of the water discharged from the discharge port of the symmetrical water injection channel was illustrated, but the present invention. is not limited to this. For example, the valve element of the water-injection check valve may not be provided with a pressure-receiving portion, but may receive water pressure at its outer peripheral portion or tip portion.

Further, in the above-described embodiment, the fuel injection valve provided with two water injection check valves was exemplified, but the present invention is not limited to this. In the present invention, the number of water injection check valves provided in the fuel injection valve may be one, or may be three or more. For example, the third or more water injection check valves may be provided at the rear end of the injection valve main body of the fuel injection valve, or may be provided at the junction of the pipe from the fuel injection pump and the pipe from the water injection pump. good.

In addition, the present invention is not limited to the above-described embodiment, and the present invention also includes a configuration in which the above-described constituent elements are appropriately combined. In addition, other embodiments, examples, operation techniques, etc. made by those skilled in the art based on the above-described embodiments are all included in the scope of the present invention.

REFERENCE SIGNS LIST 1 nozzle 2 needle valve accommodating portion 3 storage portion 4 nozzle hole 5 tip oil passage 6 needle valve 7 oil passage in the needle valve 8 communication hole 10 nozzle clamping metal fitting 11 injection valve main body 12 check valve accommodating portion 20 water injection check valve 21 Valve body 22 Valve body oil passage 23 Pressure receiving portion 24 Valve seat 25 Valve seat oil passage 26 Check valve spring 27 Valve body receiving portion 28 Receiving portion oil passage 29 Insertion hole 30 Valve body clamping hardware 40 Injection valve body 41 Receiving portion 50 Needle valve spring 51 Spring bearing portion 52 Oil passage in spring bearing portion 60 Water injection check valve 61 Valve body 62 Oil passage in valve body 63 Pressure receiving portion 64 Valve seat 65 Oil passage in valve seat 66 Check valve spring 67 Valve body receiving portion 68 Receiving portion oil passages 71, 72, 81 Columnar water injection passages 73, 75, 82 Annular water injection passages 74, 76, 84 Symmetrical water injection passages 90 Fuel supply pipes 91, 92, 93 O-ring 100 Fuel injection valve F1 Axial direction F2 Radial direction P1 1st water injection position P2 2nd water injection position

Claims (3)

In a fuel injection valve that injects fuel and water from a nozzle hole into a combustion chamber in a cylinder of a marine diesel engine,
a fuel oil passage for circulating the fuel pressure-fed from the fuel injection pump;
a needle valve for releasably blocking communication between the fuel oil passage and the injection hole;
a needle valve spring that biases the needle valve toward the injection hole so as to block communication between the fuel oil passage and the injection hole;
a water injection channel for injecting the water into a predetermined position of the fuel oil channel;
a water injection check valve that is interposed between the needle valve and the needle valve spring and blocks communication between the fuel oil passage and the water injection passage so as to be openable;
with
The water injection passage comprises a symmetrical water injection passage formed axially symmetrically about the central axis of the operation direction of the water injection check valve and having a discharge port facing the water injection check valve ,
The water injection check valve includes a valve body provided with a pressure receiving portion that receives the pressure of the water from the symmetrical water injection passage over the outer circumference,
A fuel injection valve characterized by: 2. The fuel injection valve according to claim 1 , wherein said symmetrical water injection passage comprises a plurality of water passages formed at equal angular intervals around the central axis in the direction of operation of said water injection check valve. 3. The fuel injection valve according to claim 1, wherein the water injection passage has an annular water injection passage surrounding the water injection check valve.

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